The present invention is related to a pump for a dialysis system, and more particularly to a pump and method of using the pump with a completely wearable dialysis or hemodiafiltration system. Furthermore, the present invention relates to a dual channel pulsatile pump cartridge and more particularly, to a method and apparatus for valving a the dual channel pulsatile pump cartridge that provides secure open/close valving and variable half-cycle fluid flow between channels.
Hemodialysis is a process by which microscopic toxins are removed from the blood using a filtering membrane such as a dialyzer. Typically, hemodialysis is administered in intermittent three to four hours sessions, which take place two or three times per week. The outcomes of renal replacement therapy in the form of hemodialysis remain dismal regarding the quality of life, morbidity and mortality of these unfortunate patients. A growing body of literature and research that indicates that daily dialysis may be conducive to numerous biochemical and clinical improvements as well as in quality of life and potentially increased longevity of end-stage renal disease patients. However, the implementation of daily dialysis is almost impossible due to manpower and cost constraints. Furthermore, Continuous Renal Replacement Therapy (CRRT) over intermittent dialysis since far more toxins can be removed from the blood using CRRT seven days a week, twenty-four hours a day. Some advantages of CRRT include an expected decrease rate of morbidity and mortality, a decrease in the amount of medications required, a decrease in fluid intake and dietary restrictions, and numerous improvements in the quality of life of the ESRD patients
Existing CRRT machines are large, heavy machines adapted to provide around the clock dialysis, hemofiltration or a combination of both to individual patients. The existing CRRT machines are cumbersome and must be hooked to electrical outlets and several feet of tubing. In addition, these machines require a continuous supply of gallons of fresh water to create dialysate fluid. Further, a patient must remain connected to the existing heavy and cumbersome CRRT machine for many hours, limiting his or her ability to perform normal every day activities.
An additional problem with existing dialysis machines, is that frequent reconnection to the machine requires accessing blood flow by puncturing an arteriovenous shunt. These shunts only last for limited periods of time and are subject to infection, clotting and other complications that result in numerous hospitalizations and repeated surgical interventions.
On the other hand, implementation of daily dialysis encounters obstacles that make its accomplishment in a large scale practically impossible. Some of these obstacles include the inability or unwillingness of most patients to dialyze at home, the lack of manpower both in nurses and technicians to provide more treatments in the dialysis units, and the reluctance of governmental payers to shoulder the expense of additional procedures. Also, its implementation would not only take time, but major capital investments are required to build additional capacity in dialysis units. Although home dialysis might be the answer to the problem, most patients are unable or unwilling to use home dialysis machines. Thus, the need for a technological solution that will allow for increased dialysis time without incurring additional costs or necessitating additional manpower.
Continuous renal replacement therapy (CRRT) allows significantly higher doses of dialysis, but is unsuitable for treating End-Stage Renal Disease (ESRD) patients because the machines are heavy, attached to a wall electrical outlet and require many gallons of water.
Unsuccessful attempts have been made to create a prescription or a commercially available wearable dialysis device or Wearable Artificial Kidney (WAK) that can provide CRRT. Because of the bulky nature of typical dialyzers and associated sorbent devices, the concept of a wearable dialysis device or WAK has yet to become a reality for dialysis patients. In view of the above disadvantages, there continues to be a substantial need for a portable, wearable CRRT device, which can be used substantially continually, 24 hours a day, seven days a week. There is also a need for improved subsystems, such as pumps, sensors and the like, that can be incorporated into a WAK so that the WAK can truly operate as a CRRT device.